Should NEWBASE controller work with relay board?
Normally the max current of controller is around 400mA, further lower than the fan motor current, so it would need a relay board to extend the current so that to load the fan motor.
But some models of NEWBASE controller could cover the 20A fan motor at most, in this case, the controller could be connected to fan motors directly , not need a realy board. For example, CG220218 model variant products. (http://www.newbasecn.com/mini-bus-truck-van-car-air-conditon-controller/cg220218-controller.html)
What's more, in NEWBASE PWM control system, the PWM module which is for fan motor speed regulation working with PWM controller do not need any relay board or control box.